Inventory comprises maintaining a supply of items in an area for retrieval by customers. In a retail store, merchandise is placed or “stocked” on shelves, racks, and stands for display and retrieval by customers. Stocking shelves is an essential function of retail stores. An item not on a shelf cannot be sold. Consumer packaged good companies (referenced herein as a company or companies) are particularly concerned when their product is not on the shelf. The company may lose the sale in addition to a customer if the consumer tries a competing brand and prefers the competing brand, threatening a loss of future sales from that consumer.
During a promotion, a company spends a great amount of money advertising a product. If the campaign is successful, a new customer will purchase the advertised product, try the product, and become a loyal customer of the product and the company. If the promoted product is not on the shelves, those advertising dollars are wasted.
The condition of an item missing from the shelf is called out-of-shelf. The out-of-shelf item may be in a back room and simply needs to be stocked on the shelf. If the out-of-shelf item is not in the store, the item is requested from a distribution center or replenished from the manufacturer. An item may be located at several locations in the store, so an item that is out-of-shelf in one location may be redistributed from other locations in the store.
Typically a store employee is assigned the task of inventorying product on the shelf and replenishing an out-of-shelf product, an action called “facing the shelves”. In a large store comprising, for example, 50,000 square feet with thousands of items, many employees are required to check for out-of-shelf items and replenish the shelves. This labor-intensive task is expensive and, if not performed frequently (i.e., nightly), can result in losses of sales and customers to the store and companies providing products.
Store managers and product manufactures are also concerned with the appearance of merchandise on shelves (are they in their proper place, label facing outward for desired appearance to the shopper). The condition of shelves and products on the shelves reflects an image of the retail store to the customer; store managers and product manufacturers wish to maintain a high-quality image to customers. Continual review of merchandise on shelves is required to maintain this appearance.
The location of items placed on shelves is also of concern to retailers and companies. Some manufactures pay for specific product placement, e.g. eye level. Firms may be hired to examine (audit) product placement, to verify that a retail store is in compliance with placement agreements. For a large chain of stores, the corporate office wishes to verify that regional stores are in good shape; the aisles are clear of obstructions that may cause injury, and that the appearance of merchandise meets company standards. The corporate office relies either on the assessment of the store manager or a first-hand impression of the state of the store by an employee of the corporate office. Monitoring regional stores can be expensive if there are hundreds of stores in geographically diverse locations.
The appearance of the shelves is also important to the store manager, who may not have the time to walk all the aisles. Misplaced items and shelves in disarray detract from the impression the store leaves on the customer, potentially losing sales and customers.
Warehouse stores often use very tall shelves (e.g. 18 feet) and store inventory on the top of shelves, too high to be viewed from the ground. To physically check stock, the employee is required to use mobile stairs or a forklift device. Locating stock in such locations for inventory purposes or to locate an item for a customer is time consuming and potentially dangerous.
Conventional methods for checking shelf inventory, while essential for maintaining product availability for purchase, are labor intensive, expensive and time consuming. Typically, a store employee views each shelf in the retail store, noting which products are running low or are out of stock. The employee may use a wireless-networked barcode reader to flag products that are low or out of stock. Once flagged, the products are retrieved from warehouse stock or ordered from the corresponding company.
One conventional approach uses radio frequency identification (RFID). The RFID system utilizes a “smart shelf”, a shelf with RFID embedded antennas that interrogate the presence of items by wirelessly reading unique RFID tags applied to each item on the shelf. Although RFID technology has proven to be useful, it would be desirable to present alternate approaches to detecting out-of-stock conditions and performing inventory tasks in retail stores.
Each product on a shelf receives an RFID tag that can be tracked by an RFID system. The RFID system addresses the “last dozen feet” problem of supply chain management, from the backroom to the cash register, monitoring item-level tracking down to the shelf. However, RFID is currently expensive to implement for low cost items in a retail store. Currently, RFID tags cost about $0.25 per tag. When placed on a $2.00 item such as a tube of toothpaste, the cost of an RFID tag when compared to the cost of the item is substantial. RFID readers contribute additional overhead cost for each item in the store. Consequently, an RFID system is not an economically practical solution for item level tagging of low cost items primarily due to the expense of the RFID tag that is thrown away with each item.
Considering the thousands of items in a store and the tremendous square footage of shelves in a large store (50 k to 250 k square feet), tagging items and adding instrumentation to shelves is an expensive proposition. What is therefore needed is a system and method for performing inventory using a mobile inventory robot, wherein the mobile inventory robot is an autonomous or semi-autonomous robot that can travel the store floor and image the shelves with cameras to detect out-of-stock items and report on the appearance and placement of products on the shelves. The need for such a solution has heretofore remained unsatisfied.